- FRC timer IRQ is currently in a slight off-beat (timer should be resetted every time that the mode changes, but current MAME framework doesn't seem to like it).

NOTES:

- Hardware: System24: The odd one out. Medium resolution. Entirely ram-based, no graphics roms. 4-layer tilemap hardware in two pairs, selection on a 8-pixels basis. Tile-based sprites(!) organised as a linked list. The tilemap chip has been reused for model1 and model2, probably because they had it handy and it handles medium res.

- 16th June 2013: Charles MacDonald - I've updated the Sega System 24 hardware notes with some new findings and corrections to the previous version (http://cgfm2.emuviews.com/new/s24hw.txt).

- 6th April 2013: Charles MacDonald - I've been working on a System 24 project and decided to update the old hardware documentation. Almost everything has been tested that I can think of, including some unused features that games don't utilize. There's still a bit more work to do regarding wait states and rendering timings. Documents: System 24 hardware notes, V-Sync timing diagram (PNG), Scanline timing diagram (PNG) and Horizontal and vertical timings (ODS). The V-Sync diagram shows how the composite sync output has the horizontal sync pulses inverted during the V-Sync pulse. The scanline timing diagram shows the timing relationships between different events in units of pixels. If possible, I'll try to get more updates done this year.

- 0.142u1: Removed machine\segas24.c. Start untangling the Sega System 24 Vogon poetry Atari Ace left is his wake. Apply the new timing implementation per cgfm's analysis. Gain ground is going to be stuck in free play mode [O. Galibert].

- 0.121u2: Changed system24.c to segas24.c driver. Cleaned up inputs in the System 24 driver [Sonikos]: Fixed dips in qrouka, sgmastc, sgmastcj, roughrac and qsww. Fixed input in dcclub, sgmastc, sgmastj and qrouka (the last is still missing input for the 3rd & 4th player). Added more description for each game: region, system (rom or floppy based) and version.

- 15th December 2003: Olivier Galibert sent another update to the Sega System 24 driver fixing a bunch of things.

- 13th December 2003: Olivier Galibert sent in an update to the Sega System 24 driver, improving HotRod to near perfection and adding all the encrypted games (which naturally don't work).

- 0.71u3: Brad Oliver fixed compile problems in vidhrdw\segaic24.c.

- 0.68: Added system24.c driver, machine\system24.c, vidhrdw\system24.c, includes\system24.h and vidhrdw\segaic24.c/h. There are still a lot of issues with this driver, but by including it now hopefully it can develop and also aid others looking at this system saving them time etc.

- 24th April 2003: David Haywood submitted Olivier Galibert's System 24 driver separated from the rest of the Sega rewrite. It supports Quiz Ghost Hunter, Tokoro-san no MahMahjong, Tokoro-san no MahMahjong 2 and Quiz Mekurumeku Story. Bonanza Brothers has serious graphics problems and Hot Rod boots up but doesn't work at all, so they aren't yet playable.

- 10th December 2001: Olivier Galibert reported some progress on the Sega System 24 driver. Hot Rod, Tokoro-san no MahMahjong and Tokoro-san no MahMahjong 2 are all playable with sound.